Fact Sheet: Coenzyme Q10 (CoQ10, Ubiquinone, Ubiquinol)

Written by Parris M. Kidd, PhD

Medically Reviewed by Michelle Simon, PhD, ND

Published April 17, 2025
Last Updated April 17, 2025

Overview

Coenzyme Q10 (CoQ10) is a fat-soluble essential nutrient. Scientists have studied CoQ10 extensively, and its main functions in the body are relatively well understood.¹^,²^,³

CoQ10 is called a coenzyme because it’s needed for numerous human enzymes. Within our cells, CoQ10 molecules are continually being switched between two forms. One form, called ubiquinone (CoQ), is an oxidized state. The other, ubiquinol (CoQH2), is a reduced state. This back-and-forth “cycling” process is the basis of CoQ’s vital roles in human health.

Uses

CoQ10 is mainly used as a dietary supplement. It’s also available as eye drops and for other topical applications.³

CoQ10 is essential to the functioning of mitochondria, our cells’ tiny powerhouses that make at least 95 percent of the body’s energy.¹^,²^,³ The mitochondrial energy enzymes continually cycle CoQ10 between CoQ and CoQH2 in order to generate energy. CoQ10 supplements could be beneficial for someone with impaired mitochondrial function.

As an antioxidant, CoQ10 functions within cell membranes to neutralize potentially harmful free radicals and other oxidants, providing antioxidant backup for vitamin E in whole-cell protection. The blood lipoproteins that transport cholesteroland other fat-soluble nutrients also contain CoQ10, protecting against oxidative breakdown.⁴

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Deficiency

The body naturally produces about 500 mg of CoQ10 daily.⁵ Because most people likely get less than 10 mg per day, supplements are more effective for correcting depletion or deficiency.

Primary CoQ10 deficiency is genetic, caused by mutations in genes that control its production. Although such genetic mutations are very rare, they can result in death within the first year of life.¹^,²^,⁶ Mutations that impair CoQ10 metabolism cause secondary CoQ10 genetic deficiency, another condition for which timely CoQ10 intervention can be lifesaving.¹^,²^,⁶^,⁷
Tissue sampling is necessary to confirm CoQ10 deficiency.- Because blood CoQ10 levels vary substantially with food consumption and plasma lipoprotein content, blood testing is insufficient. However, abnormally low blood levels often reflect tissue deficiency, as was first established for heart failure patients.⁸

Benefits

Woman holds cut-out of red heart in front of chest

CoQ10 has proven widely beneficial in numerous double-blind, placebo-controlled, randomized controlled trials (RCTs), with several established benefits:

1. Counters oxidative stress. Oxidative stress (OS) develops when oxidative toxins exceed the body’s antioxidant defenses. CoQ10 supplementation helps counter OS by enhancing antioxidant protection.⁸

2. Improves Duchenne muscular dystrophy and certain other inherited neuromuscular diseases. People with these diseases tend to have low muscle CoQ10 levels, often with mitochondrial abnormalities, and typically benefit from CoQ10 supplementation.⁷

3. Saves heart failure patients. A failing heart muscle typically has abnormally low CoQ10 content,⁸ and meta-analysis of data from 33 RCTs established that supplementation can significantly improve moderate to severe heart failure. Combined with conventional therapy, CoQ10 improved 2-year survival rates, enhanced heart function, and reduced hospitalization rates.⁹^,¹⁰

Heart failure researchers have called for elevating total blood CoQ10 (i.e., CoQ+CoQH2) to at least 3 micrograms (mcg) per milliliter (mL) of plasma (3 mcg/mL),⁸ which can typically be achieved with 400 mg/day of CoQ for one to two months. CoQ10 has also shown potential benefits for other heart muscle diseases.¹¹

Hyperthyroid patients often have oxidative stress, low CoQ10 in their blood and thyroid tissue, and sometimes heart disease. Supplementation can improve heart symptoms associated with these conditions.¹²

4. Protects against statin muscle damage. Statin drugs impair enzymes that produce CoQ10, thereby depleting muscle CoQ10 content and causing clinical muscle damage.¹. Taking CoQ10 to prevent or reverse damage from statins is highly advisable, given its safety and ease of use.¹³

5. Improves reproductive health.³^,¹⁴ A meta-analysis of data from six RCTs found CoQ10 supplementation improved in vitro fertilization outcomes for women.¹⁴ For males, supplementation increased sperm CoQ10 levels from abnormal lows and restored sperm capacity to fertilize an egg.³

6. Benefits diseases with low tissue or blood CoQ10 levels.¹^,²^,³^,⁶^,¹⁵^,¹⁶^,¹⁷^,¹⁸ CoQ10 supplementation often benefits patients with attention-deficit/hyperactivity disorder, ataxias, type 2 diabetes, Down syndrome, fatigue,¹⁵ fibromyalgia, lung diseases (asthma, chronic obstructive pulmonary disease, COVID–19), kidney disease (especially when taking statins), migraines¹⁶ and related cyclic vomiting syndrome,¹⁷ multiple sclerosis, mucopolysaccharidosis, non-alcoholic fatty liver disease, Parkinson’s disease, periodontal disease, various cancers, and cancer chemotherapy. Supplementation can be lifesaving for intensive care patients with low blood CoQ10 levels.¹⁸

7. Lowers elevated cholesterol. One large meta-analysis (comprising 50 RCTs) suggests taking 200 mg (minimum) of CoQ10 daily can lower blood total cholesterol.¹⁹ Two additional meta-analyses indicate CoQ10 may improve cholesterol and triglyceride levels among people with polycystic ovary syndrome.²⁰

8. Improves exercise performance. Intensive aerobic exercise can lower CoQ10 blood levels.¹^,²¹ In one trial, young men who took CoQH₂ (200 mg/day for one month) maintained healthy blood levels while performing intense long-distance runs, despite the physical stress.²² In another trial, CoQH2 (300 mg/day for 6 weeks) improved aerobic performance of trained athletes.²¹

9. Anti-inflammatory. Pro-inflammatory balance depletes CoQ10, and supplementation can lower major blood inflammation markers: C–reactive protein (CRP), interleukin–6 (IL–6), and tumor necrosis factor–alpha (TNF-alpha).²³ CoQ10 supplementation has also reduced inflammation in rheumatoid arthritis patients.³

10. Promotes healthy aging. The body’s CoQ10 production peaks at about age 20.¹ With age, tissue levels decline, especially in the heart (some people lose more than 50 percent),²^,⁶ brain, and skin.¹ Middle-aged and older adults may benefit from supplementing with CoQ10.

Dose Recommendations

Supplementing with CoQ or CoQH2 raises blood and tissue levels of total CoQ10 (CoQ+CoQH2). Neither has shown superior clinical benefit over the other, but most clinical trials have been conducted with CoQ.

To maintain blood (plasma) levels within the normal range (approximate average 1–1.2 mcg/mL plasma²⁴), daily CoQ/CoQH2 doses of at least 200 mg/day are appropriate, preferably taken with food in two or three divided doses.

For genetic CoQ10 deficiencies in children, supplementation with CoQ at 4 mg/kg body weight per day for four years is confirmed safe.⁶

In adults, CoQ at 2,400 mg/day for 5 years is reported safe and well tolerated,²⁵as is CoQH2 at 1,500 mg/day for 48 weeks.²⁶ Plasma levels of total CoQ10 averaging 4.4–8.0 mcg/mL were reported safe over five years.²⁵

The substantial body of clinical trial evidence strongly supports the use of CoQ10—whether in the form of CoQ or CoQH2—for people with plasma CoQ10 levels below 1 mcg/mL, as well as for a range of conditions, including low energy, mitochondrial disease, inflammation, infections, toxin exposure, and declining organ function.

Application (CoQ or CoQH2)	Recommended Daily Dose
Maintenance (sustaining 1.0 mcg/mL)	200 mg
Possibly deficient (below 1.0 mcg/mL)	200–300 mg
Deficient (low tissue level)	300–400 mg
Heart failure, other disease	400–1,200 mg

Side Effects

CoQ10 does not cause serious adverse reactions, as demonstrated in numerous clinical trials, some of which have lasted as long as five years. Mild gastric disturbance and headaches have been reported, with possible increased severity above 1,200 mg/day. CoQ10 is safe for use during pregnancy.²⁷

Interactions

The body’s CoQ10 content can be depleted by drugs, including statins, the antidepressant amitriptyline, female oral contraceptives and hormone replacement therapies, and bisphosphonates for bone health.¹

Taking CoQ10 may interfere with warfarin, and an animal study suggests it can interact with theophylline.²⁸

Food Sources

CoQ10 is most abundant in fish, chicken, pork, beef, and other muscle meats, liver and other animal organs, and some bee pollens. Plant foods contain less of this vital nutrient than animal foods, with avocado, broccoli, spinach, peanuts, pistachios, and dates providing the most. Being heat-sensitive, CoQ10 is vulnerable to cooking. Total dietary CoQ10 intake is about 5 mg/day.²⁹

Footnotes

1
Staiano C, García-Corzo L, Mantle D, Turton N, Millichap LE, Brea-Calvo G, Hargreaves I. Biosynthesis, deficiency, and supplementation of coenzyme Q. Antioxidants (Basel). 2023 Jul 21;12(7):1469. https://doi.org/10.3390/antiox12071469
2
Mantle D, Dewsbury M, Hargreaves IP. The ubiquinone-ubiquinol redox cycle and its clinical consequences: an overview. Int J Mol Sci. 2024 Jun 20;25(12):6765. https://doi.org/10.3390/ijms25126765
3
Mantle D, Turton N, Hargreaves IP. Depletion and supplementation of coenzyme Q10 in secondary deficiency disorders. Front Biosci (Landmark Ed). 2022 Dec 19;27(12):322. https://doi.org/10.31083/j.fbl2712322
4
Stocker R, Bowry VW, Frei B. Ubiquinol-10 protects human low density lipoprotein more efficiently against lipid peroxidation than does alpha-tocopherol. Proc Natl Acad Sci USA. 1991;88(5):1646-50. https://pubmed.ncbi.nlm.nih.gov/2000375/#
5
Mantle D, Hargreaves IP. Efficacy and safety of coenzyme Q10 supplementation in neonates, infants and children: an overview. Antioxidants (Basel). 2024 Apr 26;13(5):530. https://doi.org/10.3390/antiox13050530
6
Folkers K, Simonsen R. Two successful double-blind trials with coenzyme Q10 (vitamin Q10) on muscular dystrophies and neurogenic atrophies. Biochim Biophys Acta. 1995 May 24;1271(1):281-6. https://doi.org/10.1016/0925-4439(95)00040-b
7
Mortensen SA. Perspectives on therapy of cardiovascular diseases with coenzyme Q10 (ubiquinone). Clin Investig. 1993;71(8 Suppl):S116-23. https://doi.org/10.1007/BF00226851
8
Dabbaghi Varnousfaderani S, Musazadeh V, Ghalichi F, et al. Alleviating effects of coenzyme Q10 supplements on biomarkers of inflammation and oxidative stress: results from an umbrella meta-analysis. Front Pharmacol. 2023 Aug 8;14:1191290. https://doi.org/10.3389/fphar.2023
9
Mortensen SA, Q-SYMBIO Study Investigators. The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure. Results from Q-SYMBIO: a randomized double-blind trial. JACC Heart Fail. 2014 Dec;2(6):641-9. https://doi.org/10.1016/j.jchf.2014.06.008
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Xu J, Xiang L, Yin X, et al. Efficacy and safety of coenzyme Q10 in heart failure: a meta-analysis of randomized controlled trials. BMC Cardiovasc Disord. 2024 Oct 26;24(1):592. https://doi.org/10.1186/s12872-024-04232-z
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Zozina VI, Covantev S, Goroshko OA, et al. Coenzyme Q10 in cardiovascular and metabolic diseases: current state of the problem. Curr Cardiol Rev. 2018;14(3):164-74. https://pubmed.ncbi.nlm.nih.gov/29663894/#
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Mantle D, Hargreaves IP. Coenzyme Q10 and autoimmune disorders: an overview. Int J Mol Sci. 2024 Apr 22;25(8):4576. https://pubmed.ncbi.nlm.nih.gov/38674161
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Ahmad K, Manongi NJ , Rajapandian R , et al. Effectiveness of coenzyme Q10 supplementation in statin-induced myopathy: a systematic review. Cureus. 2024 Aug 31;16(8):e68316. https://pubmed.ncbi.nlm.nih.gov/39350827/#
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Lin G, Li X, Yie SLJ, Xu L. Clinical evidence of coenzyme Q10 pretreatment for women with diminished ovarian reserve undergoing IVF/ICSI: a systematic review and meta-analysis. Ann Med. 2024 Dec;56(1):2389469. https://pubmed.ncbi.nlm.nih.gov/39129455
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Mizuno K, Sasaki AT, Watanabe K, Watanabe Y. Ubiquinol-10 intake is effective in relieving mild fatigue in healthy individuals. Nutrients. 2020 Jun 2;12(6):1640. https://pubmed.ncbi.nlm.nih.gov/32498248
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Kaur K, Hernandez V, Al Hajaj VW, et al. The efficacy of herbal supplements and nutraceuticals for prevention of migraine: can they help? Cureus. 2021 May 6;13(5):e14868. https://pubmed.ncbi.nlm.nih.gov/33972917
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Venkatesan T, Levinthal DJ, Tarbell SE, et al. Guidelines on management of cyclic vomiting syndrome in adults by the American Neurogastroenterology and Motility Society and the Cyclic Vomiting Syndrome Association. Neurogastroenterol Motil. 2019 Jun;31 Suppl 2(Suppl 2):e13604. https://pubmed.ncbi.nlm.nih.gov/31241819
18
Hasanloei MAV, Zeinaly A, Rahimlou M, et al. Effect of coenzyme Q10 supplementation on oxidative stress and clinical outcomes in patients with low levels of coenzyme Q10 admitted to the intensive care unit. J Nutr Sci. 2021 Jul 12;10:e48. https://pubmed.ncbi.nlm.nih.gov/34290862
19
Liu Z, Tian Z, Zhao D, et al. Effects of coenzyme Q10 supplementation on lipid profiles in adults: a meta-analysis of randomized controlled trials. J Clin Endocrinol Metab. 2022 Dec 17;108(1):232-249. https://pubmed.ncbi.nlm.nih.gov/36337001
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Hu X, Wang W, Su X, et al. Comparison of nutritional supplements in improving glycolipid metabolism and endocrine function in polycystic ovary syndrome: a systematic review and network meta-analysis. PeerJ. 2023 Nov 13;11:e16410. https://pubmed.ncbi.nlm.nih.gov/38025704
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Alf D, Schmidt ME, Siebrecht, SC. Ubiquinol supplementation enhances peak power production in trained athletes: a double-blind, placebo-controlled study. J Int Soc Sports Nutr. 2013 Apr 29;10:24. https://pubmed.ncbi.nlm.nih.gov/23627788
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Orlando P, Silvestri S, Galeazzi R, et al. Effect of ubiquinol supplementation on biochemical and oxidative stress indexes after intense exercise in young athletes. Redox Rep. 2018 Dec;23(1):136-145. https://pubmed.ncbi.nlm.nih.gov/29734881
23
Hou S, Tian Z, Zhao D, et al. Efficacy and optimal dose of coenzyme Q10 supplementation on inflammation-related biomarkers: A GRADE-Assessed systematic review and updated meta-analysis of randomized controlled trials. Mol Nutr Food Res. 2023 Jul;67(13):e2200800. https://pubmed.ncbi.nlm.nih.gov/37118903
24
Pravst I, Aguilera JCR , Rodriguez ABC, et al. Comparative bioavailability of different coenzyme Q10 formulations in healthy elderly individuals. Nutrients. 2020 Mar 16;12(3):784. https://pubmed.ncbi.nlm.nih.gov/32188111
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McGarry A, Huntington Study Group. A randomized, double-blind, placebo-controlled trial of coenzyme Q10 in Huntington disease. Neurology. 2017 Jan 10;88(2):152-159. https://pubmed.ncbi.nlm.nih.gov/27913695
26
Mitsui J, Matsukawa T, Uemura Y, et al. High-dose ubiquinol supplementation in multiple-system atrophy: a multicentre, randomised, double-blinded, placebo controlled phase 2 trial. EClinicalMedicine. 2023 Apr 14;59:101920. https://pubmed.ncbi.nlm.nih.gov/37256098/#
27
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29
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About The Author(s)

Medical Editor Writer

Parris M. Kidd, PhD

Parris M. Kidd, PhD, a thought leader in dietary supplement application, has developed and overseen quality programs for numerous supplement brands. He earned his BSc from the University of the West Indies in Jamaica and completed his PhD at the University of California, Berkeley. Dr. Kidd is a steadfast advocate for enhancing product safety and efficacy through rigorous clinical research.

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